Corrosion inhibiting composition comprising 4-ethyl-1-octyn-3-ol



United States Patent ()titice 3,249,548 CORROSION INHIBITING COMPOSITION COM- PRISING 4-ETHYL-1-OCTYN-3-0L Charles 0. Herman, Fords, and John G. Funkhouser, New Brunswick, N.J., assignors, by mesne assignments, to Cumberland Chemical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 31, 1958, Ser. No. 770,923

11 Claims. (Cl. 252-136) This invention relates to the inhibition of metal corrosion in acid solutions. This invention is particularly directed to the use of 4-ethyl-l-octyn-3-ol, which has the structural formula:

HCEC-CHOHCHzCHzCHzCH;

as a corrosion inhibitor for metals in the presence of aqueous acid solutions.

Metal cleaning baths and pickling baths are usually composed of aqueous solutions of inorganic acids such as sulfuric, hydrochloric, and phosphoric acids and are useful in the cleaning of metals and metal alloys, such as aluminum, ferrous metals specifically including steel, zinc, etc.

In the use of acid baths to remove undesired metal surface coatings, additives or inhibitors in the acid bath are desirable to prevent or inhibit corrosion or erosion of the metal surfaces. If no corrosion inhibitor is present in the acid bath, the results generally will be excessive metal loss, production of undesirable metal surface properties, and excessive consumption or loss of acid. While it is well-known to use corrosion inhibitors in such acid baths, those inhibitors heretofore used have had certain disadvantages such as, instability at elevated temperatures, toxic and obnoxious properties when used in the acid baths and in certain cases poor metal surface properties resulted from their use. Also, certain prior art inhibitors are diflicult to use as they are bulky sticky solids or viscous liquids; while others have the undesirable properties of producing excessive foam and they are not soluble .or compatible with other compounds used in the corrosive systems. Still other inhibitors result in the metal having poor properties, especially undesirable in electroplating operations, as poor adhesion and discolored surfaces.

It is an object of this invention to provide an improved composition and an improved method for the protection of metal surfaces against erosion or corrosion in aqueous acid solutions.

Another object of this invention is to provide a novel inorganic acid cleaning composition and a method of cleaning metals while substantially preventing or inhibiting acid attack on metal surfaces being cleaned, without interfering with the desired cleaning action.

A further object of the invention is to provide improved metal cleaning baths that may be operated at elevated temperatures.

These and other objects and advantages of this invention will be pointed out or will become apparent from the following description.

In accordance with the present invention the incorporation of a small amount of 4-ethyl-1-octyn-3-ol in aqueous inorganic acid solutions has been found to have the desirable property of inhibiting or substantially preventing the corrosive action or attack of the acid upon the metal surface being cleaned. The use of 4-ethyl-1- octyn-3-ol in acid cleaning and pickling baths does not hinder or interfere with the desired action of the acid on the oxide, rust, grease, scale or other undesirable surface material or coating which is to be removed.

3,249,548 il atented May 3, 1966 The inhibitor of this invention, 4-ethyl-1-octyn-3-ol, is useful, in general, in the inhibition of corrosion of metal surfaces in contact with aqueous acid solutions, for example, in the acidizing of oil wells, electrolytic cleaning baths, electroplating baths, and electrolytic refining of metals as well as in metal cleaning and pickling baths.

The use of 4-ethyl-1-octyn-3-ol as a corrosion inhibitor for metals in aqueous inorganic acid solutions is advantageous in that 4-ethyl-1-octyn-3-ol can be employed as a corrosion inhibitor over a wide and useful concentration range. When used as an inhibitor 4-ethyl-1-octyn- 3-ol does not produce discolored metal surfaces or undesirable properties on the metal surface in contact with the inhibited acid system. Its use as an inhibitor in metal cleaning operations while inhibiting acid attack on the metals will generally result in improved surface properties of the metals. When compared at equal concentrations 4-ethyl-l-octyn-3-ol will generally give better inhibition than other inhibitors. The inhibitor is not toxic or obnoxious when used in aqueous acid solutions; further it does not produce undesirable foam and it is soluble and compatible with other materials usually added to the aqueous acid systems. A- further advantage of this inhibitor is that it may be used at elevated temperatures to provide good corrosion inhibition.

The most effective amount of 4-ethyl-1-octyn-3-ol to be used in this invention will vary, depending generally upon the particular acid corrosive system, the particular metal exposed to acid, and the amount of acid present in the aqueous solution. The temperature and" other characteristics of the acid corrosive system will also affect the amount of inhibitor to be used.

In general, it has been found that a concentration of 4-ethyl-1-octyn-3-ol between 0.0125 to 0.5% by weight of the acid corrosive solution is an effective and desirable corrosion inhibiting concentration, with a concentration between 0.05% to 0.2% being of particular advantage. For corrosive systems at elevated temperatures above approximately 66 C. and in the range of 66 C. to C., an inhibitor concentration greater than 0.2% is most effective.

The inhibitor of this invention, 4-ethyl-l-octyn-3-ol, may be advantageously combined with other compounds, such as amine inhibitors; as for example, quaternary ammonium compounds as Arquad T and Arquad 2C, manufactured by Armour and Company; rosin-ammonia reaction products, including abietylamine derivatives; coal tar derivatives and heterocyclic nitrogen compounds; primary, secondary and tertiary amines and their alkyl hydroxy derivatives; and the ethylene oxide condensation reaction products of the preceding amines. This combination being useful as a corrosion inhibitor to inhibit or substantially prevent the corrosion of metals in contact with aqueous acid solutions. This amine, 4- ethyl-l-octyn-3-ol inhibitor combination may be used in concentrations from approximately 0.0125 to 0.5% by weight of the aqueous acid solution. The ratio of amine to 4-ethyl-1-octyn-3-ol may vary appreciably, but it has been found that a 1:1 ratio is advantageous. A particular amine-Alkyl Pyridine HB-available from Union Carbide Chemicals Company and comprising a mixture of lower alkyl pyridines as methyl, ethyl, isopropyl and propyl pyridine is useful in the amine, 4- ethyl-1-octyn-3-ol combination inhibitor. A mixture of Alkyl Pyridine HB and 4ethyl-1-octyn-3-ol comprising 0.1% of each and a total of 0.2% by weight of the aqueous acid corrosive system is effective as a corrosion inhibitor.

The following examples are illustrative of the corrosion inhibiting properties of 4-ethyl-1-octyn-3-ol. In the examples the inhibitor concentration is expressed as percent by weight of the aqueous acid solution and the acid concentration is percent by weight of the solution. The method used to determine the inhibiting properties of 4- ethyl-1-octyn-3-ol as set forth in the examples consisted in first cleaning hot rolled mild steel specimen strips (SAE 1010-1015, carbon content 0.05%0.20%), 2" x 1" x with an average surface area of 0.0313 sq. ft. and an average weight of 15.5 grams. Cleaning was accomplished by rinsing the steel coupons with trichloroethylene, then rubbing the coupon with a cloth wet with trichloroethylene. The steel coupons then were dipped in concentrated hydrochloric acid for one minute followed by an immediate rinse with distilled water. The coupon was dried by rinsing with acetone. The coupons were then weighed to obtain the original weight prior to immersion in the corrosive system for a specified time.

Various corrosive systems may be used, for example, (1) hydrochloric acid system-15% HCl maintained at 66 C. (150 F.), (2) sulfuric acid system15% H SO maintained at 86 C. (187 F.), (3) phosphoric acid system-15% H PO maintained at 71 C. (160 F.). These systems are generally representative of the aqueous acid corrosive systems usually encountered.

After immersion in the corrosive system for the specified time the coupons were removed, washed with distilled water, rinsed with acetone, air dried and again weighed. In most tests an initial live hour immersion time was used and the coupons after being weighed were again immersed in the corrosive system for a total of twenty-four hours. The cleaning of the immersed coupon was repeated.

Corrosion inhibiting properties may be described conveniently in terms of the corrosion rate. This rate being the metal loss of weight in pounds per square foot per day.

Immersion corrosion rate (lbs./ft. /day)= Coupon weight loss, grams 24 hrs/day 454 grams/lb. immersion time, hrs. surface area, sq. ft.

Example 1 The following test results illustrate the corrosion inhibiting properties of 4-ethyl-1-octyn-3-ol. Using the procedures described previously, steel coupons were immersed in 15% hydrochloric acid at 66 C. (150 F.) for periods of 5 hours and 24 hours with the 4-ethyl-1- octyn-3-ol concentration being 0.1% of the corrosive system.

A group of tests similar to Example 1, wherein the concentration of 4-ethyl-1-octyn-3-ol was varied, were performed. The 15 hydrochloric acid at 66 C. system was used along with steel coupons.

Immersion Corrosion Rate Inhibitor Concentration, percent 5 hours 24 hours 4 Example 3 The following test was conducted at a higher corrosive system temperature. The procedure used was as in the preceding examples, except the mill scale was not partially removed by an acid dip in the preparation of the steel coupons. A solution of 15 hydrochloric acid at a temperature of 82 C. (180 F.) was used. Inhibitor concentration was 0.2%.

Inhibitor: Immersion corrosion rate, 17 hours 4-ethyl-1-octyn-3-ol 0.020 None 1.585

Example 4 The following test utilized the standard procedure outlined previously with steel coupons and a 15% hydrochloric acid solution maintained at 180 F. (822 C.). Inhibitor concentration was 0.1%.

Inhibitor: Immersion corrosion rate, 24 hours. 4-ethyl- 1-octyn-3-ol 0.012 None The test sample containing no inhibitor exhibited very rapid corrosive action upon the steel with a. total weight loss of 11.643 grams or approximately of the original steel coupon; whereas after the same test period of 24 hours the sample containing inhibitor still provided substantial protection. The sample containing inhibitor continued to provide protection after a total immersion time of hours.

Example 5 The following test was conducted using the procedure of Example 3, wherein the mill scale was not partially removed by an acid dip in the preparation of the steel coupons. A solution of 15% hydrochloric acid at a temperature of 82 C. (180 F.) was used. Inhibitor concentration was percent by weight as shown.

Inhibitor: Immersion corrosion rate, 17 hours.

0.2% Alkyl Pyridine HB 0.370 0.2% 4-ethyl-l-octyn-3-ol 0.020 0.1% Alkyi Pyridine HB and 0.1% 4-ethyl-1- ootyn-3-ol 0.018 None 1.585

As widely different modifications of the invention may be made without departing from the scope and spirit of the invention, it is to be understood that the invention is not to be limited by the foregoing examples and details of description, except as defined by the following claims.

We claim:

1. A method of inhibiting corrosion of metals in contact with an aqueous-inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid, which comprises incorporating from about 0.0125 percent to about 0.5 percent by weight of 4-ethyl-1-octyn-3-ol in said acid.

2. A method of inhibiting the corrosion of metals as defined in claim 1 wherein the acid is hydrochloric acid and the amount of 4-ethyl-1-octyn-3-ol is about 0.1 to about 0.2% by weight.

3. A method of inhibiting the corrosion of metals by aqueous solutions of hydrochloric acid which comprises incorporating 0.0125 to 0.5% by weight of 4-ethyl-1- octyn-3-ol in the aqueous solution of hydrochloric acid.

4. A method of cleaning metals while inhibiting corrosion of the metal which comprises contacting the metal with an aqueous inorganic acid solution selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid, containing from about 00125 percent to about 0.5 percent by weight of 4-ethyl-1-octyn-3-ol.

5. A method of cleaning a ferrous metal with aqueous inonganic acids which comprises contacting the ferrous metal with an aqueous inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid, containing from about 0.0125 percent to about 0.5 percent by weight of 4-ethyl-l-octyn-3-ol.

6. A composition consisting essentially of water, from about 0.0125% to about 0.5% by Weight of 4-ethyl-1- octyn-3-ol, and an inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid.

7. A composition consisting essentially of Water, from about 0.012'5% to about 0.5% by weight of 4-ethyl-1- octyn-3-ol, and hydrochloric acid.

8. A composition consisting essentially of water, from about 0.2% to about 0.5 by weight of the combination of 4-ethyl- 1 octyn-3-ol and a. lower alkyl pyridine, and an inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid, said 4-ethyl-1-octyn-3-ol and said lower alkyl pyridine being present in a 1:1 ratio.

9. A method of inhibiting corrosion of metals in contact with an aqueous inorganic acid selected from the group consisting 'ofhydrochloric acid, sulfuric acid, and phosphoric acid, which comprises incorporating a corrosion inhibiting amount of at least 0.2% by weight of 4-ethy1-1-octyn-3-ol in said inorganic acid, said inorganic acid being at a temperature within the range of 66 C. to 100 C.

10. An aqueous solution of an inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid and phosphoric acid containing as a corrosion inhibitor an effective amount of 4-ethyl-1-octyn-3-ol.

11. An aqueous solution as defined in claim'10 wherein said acid ishydrochloric acid and the amount of 4-ethyl- 1-octyn-3-ol is about Oil to about 0.2% by Weight.

8 References Cited by the Examiner UNITED STATES PATENTS 1,460,395 7/ 1923 Vogel 252-148 1,678,775 7/1928 Gravell 23-139 1,723,923 8/1929 Davidson 252-148 2,037,762 4/ 1936 Cole 252-148 2,043,257 6/1936 Mi-ssbach 260-6525 2,775,624 12/1956 Skeeters 260-6525 2,805,257 9/ 1957 Lowes et a1 260-609 2,806,067 9/1957 Monroe et a1. 260-6 17 2,814,593 11/1957 Beiswanger et a1 252-148 2,838,458 6/1958 Bachtel 252-171 2,846,294 8/1958 Patterson et a1 252-146 2,913,408 11/1959 Pumpelly et a1. 252-146 XR 2,955,083 10/1960 Levin 252-855 13,049,496 8/ 1962 Monroe et a1. 252-146 3,107,221 /1963 Harrison et a1 252-148 3,113,113 112/1963 Marsh et a1 252-148 XR FOREIGN PATENTS 764,233 12/ 1956 Great Britain.

OTHER REFERENCES Corrosion Handbook by Uhlig, pp. 910-912, pub. by John Wiley & Sons, Inc., New York (1948).

JULIUS GREENWALD, Primary Examiner. 

5. A METHOD OF CLEANING A FERROUS METAL WITH AQUEOUS INORGANIC ACIDS WHICH COMPRISES CONTACTING THE FERROUS METAL WITH AN AQUEOUS INORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC ACID, SULFURIC ACID, AND PHOSPHORIC ACID, CONTAINING FROM ABOUT 0.0125 PERCENT TO ABOUT 0.5 PERCENT BY WEIGHT OF 4-ETHYL-1-OCTYN-3-OL.
 8. A COMPOSITION CONSISTING ESSENTIALLY OF WATER, FROM ABOUT 0.2% TO ABOUT 0.5% BY WEIGHT OF THE COMBINATION OF 4-ETHYL-1-OCTYN-3-OL AND A LOWER ALKYL PYRIDINE, AND AN INORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC ACID, SULFURIC ACID, AND PHOSPHORIC ACID, SAID 4-ETHYL-1-OCTYN-3-OL AND SAID LOWER ALKYL PYRIDINE BEING PRESENT IN A 1:1 RATIO. 